BM-21 "Grad"（俄语：БМ-21 "Град"，字面意为“冰雹”）是一种苏联设计的自行式122毫米多管火箭炮系统。该系统与M-21OF火箭弹于1960年代初期首次研发，并于1969年3月中苏边境冲突期间首次投入实战。BM代表boyevaya mashina（俄语：боевая машина – 战斗车辆），而昵称grad意为“冰雹”。包含BM-21发射车与M-21OF火箭弹的完整系统被命名为M-21野战火箭系统，通常更广为人知的名称是Grad多管火箭炮系统。
在北约国家中，该系统（无论是完整系统还是仅发射车）最初被称为M1964。多个国家曾仿制Grad或研发了类似系统。在俄军服役中，其预定替代型号为9A52-4 Tornado。许多国家基于BM-21 Grad制造了类似的122毫米多管火箭炮系统。
A BM-21-1 launch vehicle during a military parade in Yekaterinburg, May 2009.
A BM-21 launch vehicle.
The 9P138 launch vehicle of the Grad-1 multiple rocket launcher system.
A BM-21V VDV variant.
A Grad-P single tube launcher system
A Belarusian BM-21A "BelGrad"
A WS-22 SPMRL of the Bangladesh Army .
A LRSV-122 M-96 "Tajfun
A RM-70 launch vehicle, a Czechoslovak variant with the BM-21 launch vehicle launcher unit.
A Georgian RS-122, a heavily upgraded and automated version of the Soviet BM-21 based on the Ukrainian KrAZ-63221 chassis
A WR-40 Langusta, a deeply modernized and automated version, of the Soviet BM-21 based on the Jelcz P662D.35 6x6 truck , displayed at the MSPO 2007.
A Serbian LRSVM Morava
A Ukrainian BM-21 Bastion-1 based on a KrAZ-260 chassis
A Ukrainian Bastion-02
A fired 122 mm projectile of a RM-70 multiple rocket launcher stuck in muddy land in Vakarai , Batticaloa during the Sri Lankan Civil War (2007).
A Djiboutian Army Rocket Launcher
A BM-21 on display near the Karen Demirchyan Complex , Yerevan, Armenia
